The best training I’ve found is in Michael Raduga’s the phase. He has a free seminar recorded on youtube which we have linked here, and he has a book called “The Phase”.
You do not need the “third eye open” - this technique does not rely on the concepts from yoga at all. The key is to know several techniques and keep trying different ones in a session until one works.
I also had success combining these techniques with Mexican Dream Herb tincture taken as a supplement before bed.